1. Field of the Invention
The present invention relates to a recording tape cartridge which rotatably accommodates, within a case, a reel around which a recording tape, such as a magnetic tape or the like, is wound.
2. Related Art
A recording tape cartridge where a brake gear that is formed on an outer circumference of a brake member not to be rotated with respect to a case is meshed with an engagement gear that is formed on an inner circumference of a reel hub and the rotation of the reel with respect to the case is locked has been known (for example, refer to Japanese Patent Application Laid-Open No. 2005-196938). Further, a recording tape cartridge where a locking member is entered between a reel and case ceiling plate and displacement of the reel with respect to the case in an axis line direction is regulated has been known (for example, refer to Japanese Patent Application Laid-Open No. 2005-276415).
Meanwhile, when the recording tape cartridge falls to a floor, the reel may be displaced to be inclined with respect to the case due to the impact. Even in this case, a brake member where a displacement direction is regulated in only an upward-to-downward direction (in general, reel axis line direction) with respect to the case is rarely inclined with respect to the case and is relatively inclined with respect to the reel.
However, in the related art, due to the relative posture variation (inclination) of the brake member with respect to the reel at the time of falling, a rotation lock state of the reel by the brake member may be released. Further, as disclosed in Japanese Patent Application Laid-Open No. 2005-196938, when a mesh surface of the engagement gear and the brake gear is set to be parallel to a reel axis line, a taper for guidance at the time of the mesh cannot be formed in only an end of a teeth width direction. Therefore, in order to smoothly mesh the engagement gear and the brake gear by the relative displacement of the reel axis line direction, high precision is required in components and an assembly. Specifically, when a guide taper that is sufficient to smoothly mesh the engagement gear and the brake gear within a limited mesh stroke is provided, a mesh area that is approximately parallel to the reel axis line may be decreased, and a rotation lock state by the brake member may be released at the time of falling. In contrast, when a guide taper amount is decreased to secure a sufficient mesh surface, it is difficult to smoothly mesh the engagement gear and the brake gear. In order to achieve the smooth mesh of the engagement gear and the brake gear within the limited stroke and maintaining of the lock state with respect to the posture variation of the brake member at the time of falling, the high precision is required in the components and the assembly, as described above.